Two days after Josh Powell and his two sons died in an intense fire at their Graham, Wash., home, officials say Josh Powell carefully planned the murder-suicide and brutally attacked his sons before setting the house on fire.
As arson investigators continue to search through what's left of the Powell home, the medical examiner now says 7-year-old Charlie and 5-year-old Braden Powell suffered chop injuries to their heads and necks.
Ed Troyer, of the Pierce County Sheriff's Department, said investigators found a hatchet that they believe was used on the boys.
"We recovered a hatchet -- a small ax," he said. "It was right there with them (the bodies)."
The sheriff says their father, Josh Powell, then set the house on fire.
Troyer said, "They've found two, five-gallon cans of gas. One of them was with the bodies, the other was spread throughout the house. There were accelerants throughout the whole entire house."
Video: Helicopter footage of explosion scene (KIRO)
Police say before he carried out the murder-suicide, Powell donated his son's toys to charity and left instructions about his personal effects in multiple e-mails.
"He sent some emails out to family and a pastor and some other people making sure that everybody knew that he was gone, that he was the one that did this," Troyer said.
Powell had been under police scrutiny following the suspicious disappearance of his wife, Susan Cox Powell from their Utah home in December 2009. Six days ago he lost a battle with Susan's parents for custody of his sons.
Chuck and Judy Cox say their grandchildren were at their home playing before Sunday's court-ordered visit with Josh.
"They were having a good time and didn't want to stop and see Daddy," Chuck Cox said. "They seemed to be losing interest in going to see him."
It was Judy Cox who talked the boys into going and she says she will have to live with that regret.
"Look what happened," she said. "But I knew that they're supposed to be able to see their dad."
Chuck Cox added, "There were too many warning signs that were known, but due to legal limitations, were unable to be acted upon."
Josh Powell never mentioned Susan in his good-bye e-mails. An attorney for the Cox family says the kids had recently talked about seeing their mom in the trunk of the car the night she vanished. He also says authorities told the family that Josh Powell was likely to be arrested in the coming months.
"One of the things that was done here was he destroyed the evidence," Troyer said. "As callous as that sounds, he destroyed the evidence, because those guys could've been the best evidence against him."
For more on the case, watch Ben Tracy's full report in the video above.